This application claims the priority of German patent application 29909223.2, filed May 28, 1999, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a solenoid valve, particularly for a use in weaving machines. Solenoid valves of this type are used, for example, in air nozzle weaving machines, for steering the pneumatic woof yarn feeding medium to the main and auxiliary blow nozzles.
In the simplest case, a solenoid valve consists of a valve housing in which the valve chamber is arranged with the valve inlet and the valve outlet. In the closed condition of the valve, the valve inlet and the valve outlet are separated from one another by a valve disk disposed on a valve seat. The valve disk is driven by an electromagnetically actuated control element and can be lifted off the valve seat such that the passage between the valve inlet and the valve outlet is opened up. The valve inlet and outlet are connected with hose or tube connections for feeding and removing a pressure medium. The electric connection for the electromagnetic drive takes place by way of a corresponding connecting line.
If a defect occurs in the case of such a solenoid valve, it has been necessary to either exchange the entire valve or to at least remove the valve in order to be able to exchange the defective parts. This resulted in the disadvantage that the connections for the pressure medium to the valve inlet and the valve outlet as well as the electric connecting line had to be pulled off before the removal of the valve, which leads to considerable expenditures particularly in the case of installation positions which are difficult to access. In the case of air nozzle weaving machines, it is impossible during the weaving operation to access the solenoid valves used for controlling the auxiliary blow nozzles, because these solenoid valves are covered by the web of woven fabric moving directly over them.
Another disadvantage is the fact that, when individual components, such as the valve disk, are exchanged, the observance of the specified tolerances, as, for example, switching times, valve lift, etc., is not ensured if old components are paired with new exchange elements.
It is an object of the invention to improve a solenoid valve of the initially mentioned type such that the components subjected to wear can be rapidly exchanged.
This object is achieved according to preferred embodiments of the invention by providing a solenoid valve, particularly for a use in air nozzle weaving machines, comprising:
a valve housing with a fluid input, a fluid output and having electric contact bushes,
a first valve body which is arranged in the valve housing and which connects an inflow-side hollow space of the first valve housing by an inlet integrated in the valve body with an outflow-side valve chamber,
a second valve body for controlling a fluid flow between the valve chamber and a coaxial outlet in the first valve body, and
a fastening flange which can be rapidly connected with the valve housing and which, facing the valve housing, carries the first valve body and which, facing away from the valve housing, carries an electromagnetic drive, the drive having electric contact elements for the rapid connection with the electric contact bushes,
wherein the fastening flange, the first valve body and the second valve body as well as the electromagnetic drive together form a first valve subassembly which is subjected to a rapid exchange, and
wherein the valve housing with its connections forms a second valve subassembly which in use is fixedly arranged on the weaving machine.
The invention is based on the fact that a first valve body is sealingly accommodated in a hollow space of the valve housing, in which case at least one inlet and one outlet for a pressure medium lead into the hollow space of the valve housing, which inlet and outlet can be connected in a controlled manner inside the valve housing.
As the result of the essentially two-part construction of the solenoid valve, specifically the valve housing, which has the connections for feeding and removing the pressure medium to be steered, the first valve body arranged in the valve housing, and, on the other hand, the second valve body which carries out the actual valve functions, it is advantageously achieved that an exchange of the built-in valve parts can be carried out without the removal of the connections for the pressure medium, such as hoses and pipes.
When the first and second valve body are inserted, a fastening flange connected with the first valve body rests against the valve housing, in which case the valve housing and the fastening flange are connected with one another by means of rapidly releasable fastening devices.
The first valve body, the fastening flange and the electromagnetic drive together advantageously form a valve subassembly which can be exchanged as a unit.
Between the first valve body and the valve housing, seals are arranged which, on the one hand, provide a sealing off of the valve chamber toward the outside and, on the other hand, seal off the inlet and the outlet of the valve chamber with respect to one another.
An easy exchangeability of the valve subassembly is also promoted by the fact that a plug-type connector with electric contacts is arranged on the valve subassembly, which plug-type connector interacts with a counterpart arranged on the valve housing. The plugging of the valve subassembly into the valve housing simultaneously establishes the electric connection for driving the valve.
Another advantage of the invention is the fact that a fast and easy exchange of the defective valve subassembly can be carried out in that the quick fastening between the valve subassembly and the valve housing is released and the entire valve subassembly can be exchanged without requiring a high-expenditure demounting of the valve. Also, no loose single parts occur during the exchange of the valve subassembly, which may possibly be lost.
In addition, the valve subassembly is a pretested and operable unit so that, when it is exchanged, no subsequent testing of the exchanged valve subassembly is required. The risks of tolerance differences between the old and the new parts, which may impair the operability of the valve, are therefore eliminated.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.